简易计算器（数码管显示） 本程序为简易计算器。可以算整数且正数类型的运但是暂时没有实现其连算功能，故在每次运算之后，请按下清零键。-Simple Calculator (digital display) This procedure is simple calculator. You can count the number of positive integer and type of operation, but did not achieve its temporary functio